Work

A microscopic study into the role of grain boundaries in field-assisted protrusion growth and potential for current fluctuations in electron nanoemitters

Year: 2025

Type: article

Abstract: Studies of metallic field emission devices during operation have reported fluctuations in current and local luminosity across the emitting surface that suggest a time-dependent evolution of surface structure and morphology. One possibility is the growth of surface nanoprotrusions (NPs) driven by high Maxwell stress arising from the externally applied electric field. This aspect is probed through three-dimensional, time-dependent molecular dynamics simulations for a quantitative predictive analysis. Our results indicate NP growth for electric fields at levels of 5 × 108 V/m or higher. Material ejection from NPs is also shown to be likely for high fields acting over an extended duration. The trends agree qualitatively with reports in the literature, demonstrating the role of grain boundaries as an enabling mechanism, showing that NP growth is synergistically strengthened by the presence of surface voids, and the possibility of dynamic current fluctuations.

Source: Journal of Applied Physics

DOI: 10.1063/5.0284317

Authors: Y. M. Pokhrel, A. L. Garner, R. P. Joshi

Institutions: Texas Tech University, Purdue University West Lafayette

Language: English

Topic: Gyrotron and Vacuum Electronics Research

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,500

Funders: Air Force Office of Scientific Research, Office of Naval Research Global